Composition for making antistatic photographic films



A. F. SULZER.

COMPOSITION vFOR MAKING ANTISTATIC PHOTOGRAPHIC FILMS.

APPLlcATIoN FILED MAR. 13, 1922.

ATTORN EY i in being taken by the user.

Patented Dee. A5, w22.,

entre ALBERT F. SULZER, F RCHESTER, NEW YORK, ASSIGNR T0k ESTMN KODAK COMPANY, OF ROCHESTER, NEW YORK, A CORPORATION 0F NEW YORK.

COMPOSITIGN FOR MAKING ANTISTATIC PHGTOGERPHIC FILMS.

Original aapplication led February 21, 1921, Serial No. 446,7't33. Divided and this application tiled March '13, 1922. Serial No. 543,531.

.f o a/J w/L-om t may concern:

Be it known that I, ALBERT F. Srnlznn, a citizen of the United States of America, re,- siding at Rochester, in the county of Monroe Vand State of New York, have invented certain new and useful Improvements in Composition for Making Antistatic Photographic Films, of which the following is a full, clear,

and exact specification. l

This invention relates to a composition of t matter useful in the film making art. @ne object ofthe invention is to provide a suitable composition which may be incorporated into the lm, preferably by forming a` layer which will diminish or entii'ely prevent the formation of static. Other objects will hereinafter appear.

Due to the manipulation of sensitive photographic ilm, some times in manutacture, but more frequently in use, characteristic lines or patches may appear on development, because of electrical discharges which are created during the handling. 'Ihe ogor fogV lines which are thus formed on the film are particularly noticeable in the case of the standard species of motion picture lm, which includes a nitrocellulose support or base. It is very. important :trom the commercial standpoint to prevent this defect in the motion p1cture art, particularly when making negative film strips. lhe trouble is commonly referred to as static and will be so designated herein.

While certain camera modifications for preventing this electrical trouble'have been proposed, it is very desirable to prevent static by la proper constitution of the iilm, so that the latter may be employed in any commercial camera without any precautions 0f course, the nlm should likewise be capable of .subsequent duid treatment and drying on the customary racks or apparatus without injury.

I have discovered that lm having unexpectedlys'trong anti-static properties may be prepared by incorporating in its support a layer containing an ether of cellulose and cellulose acetate. rIhis invention is a specine application of the 'broader discovery disso closed in my co-pending application iiled February 2.1, 1921, Serial No. 446,782.

In the accompanyin drawing,- Ilig. 1 is a sectiona view on an exagger- 'applicatiom Serial No. 14:16,? 8B, -led Feb. 21,

ated scale of the preferred embodiment of my invention; '55

F ig. 2 is a sectional view on an exaggerated scale of a modification of the invention.

-layer 1, as shown in Fig. 2, but this is not the preferred form of my invention, a1- though useful photographic ilm may be made in that way.

In preparing a composition for forming the coating 3, I find it best to dissolve the cellulose ether and the cellulose acetate separately, the'two solutions being then mixed and finally diluted if desired. The following proportions and solvents are useful, but, of course,umay be widely varied. rI`he proportions are by weight. I may dissolve 45 parts of ethyl cellulose, of the kind which is insoluble in water and not injuriously softened bythe latter, in parts of ethylalcohol and 900 parts of chloroform. I separately dissolve 45 parts of acetone-soluble cellulose acetate in sullicient acetone to make a clear solution. I then combine the acetate parts. By using this method of mixing, a

properly diluted iiowable composition is provided which sets quickly when coated upon the nlm support, the volatile ingredients passing away and leaving a transparent, hard anti-static backing resistant to photographic solutions, said coating or backing comprising essentially cellulose ether and cellulose acetate.

This application is a division of my prior Having thus described my invention, what l claim as Vnew and desire tosecure by Letters Patent is:

l. A composition for 'forming a layer on an object containing a cellulose ester, said composition comprising a cellulose ether,

cellulose acetate, a solvent of said rst named ester, Oand a solvent for cellulose ether,Y said last named solvent having a stronger solvent action on said ether than said irst named solvent.

2. A, composition for forming a layer on a photographic film support containing ce1- lulose nitrate, said composition comprising cellulose ether, cellulose acetate, :amount of a nitrocellulose solvent incapable by itby itself of fully dissolving said ether.

3L A composition for forming a layer on a photographic film support containing cellulose nitrate, said composition comprising ethyl cellulose, cellulose acetate, chloroform, alcohol and acetone.

Signed at Rochester, New York, this 8th day of March, 1922.

ALBERT F. SULZER. 

